1. Field of the Invention
The present invention relates to a multiple vacuum evaporation coating device and a method for controlling the same, and more particularly to, a device and a method having a cooling device blocking the spread of heat while being able to control the rotation angle of the evaporation devices.
2. Description of the Related Art
Generally, an organic light emitting diode (OLED) display device has an indium tin oxide (ITO) anode, a metal cathode and an organic thin film multi-layer between the anode and the cathode. The organic thin film multi-layer can also have an ETL (Electron Transport Layer), an HTL (Hole Transport Layer) and an EML (Emitting Layer). The organic thin film multi-layer can also have an EIL (Electron Injecting Layer), an HIL (Hole Injecting Layer) or an HBL (Hole Blocking Layer) additionally inserted for the improvement of features of elements.
A typical OLED vacuum evaporation coating device used for forming organic thin film multi-layers generally performs the processes as follows. The first process is an ITO thin film evaporation coating process by vacuum evaporating several ITO thin film patterns on the surface of the glass substrate by sputtering. Then, as the prior process of ITO thin film, it is discharged so that the hole from ITO used for the positive pole can easily move to the emitting layer, and the surface is oxidized by using ultraviolet rays or a plasma. After that, in the organic thin film evaporation coating process, for example, by using the vacuum evaporation coating method in a high-degree vacuum state, the organic films are formed on the surface of the glass substrate. The structure of the vacuum chamber where these thin films are coated includes an evaporation source of materials, a sensor controlling the thickness of the film, a device aligning a glass substrate to the metal shadow masks, and a power source for evaporating materials. After the evaporation coating of these organic thin films is complete, the evaporation coating of metal electrodes, the evaporation coating of protective films, and the pack process are performed in order.
In this process, the evaporation coating device used in evaporation coating thin films is formed so that by heating organic and inorganic material, the material can be coated on a board installed inside the vacuum chamber. Various kinds of evaporation coating devices have been developed. The multiple vacuum evaporation coating device is used so that several evaporation sources can be rotated, and when the evaporation source is positioned at a location for heating, the melting pot is heated by a heating device. In this arrangement, the evaporation source is formed so that the melting pot having the evaporation materials can be heated by the heating device. The location for heating the melting pot includes a main heating position for evaporation coating and the preliminary heating position for heating the melting pot before being moved to the main heating position.
One drawback with this multiple evaporation coating device arrangement is that heat radiated from the melting pot was often transferred to the nearby melting pots, causing evaporation coating materials in the nearby the melting pots to discharge. Further, because the position of the main heating and the position of the preliminary heating were located far from each other, efficiency of preliminary heating was low. What is therefore needed is a multiple evaporation coating device that overcomes both these problems.